Security Bulletin
Summary
Unauthenticated users can upload unlimited files to the Langflow OSS server via the deprecated /api/v1/upload/{flow_id} endpoint without authentication or validation, leading to potential disk space exhaustion (DoS) and information disclosure through absolute file path leakage in API responses. The vulnerability affects the endpoint in langflow/api/v1/endpoints.py which lacks authentication checks and flow_id validation, allowing attackers with network access to repeatedly upload files using any UUID. Proof-of-concept demonstrates successful file upload to server cache directory with full path disclosure. Recommended mitigations include adding authentication to the route, implementing upload rate limiting and size restrictions, validating flow_id against existing flows, and returning only relative paths or filenames in responses to prevent information leakage.
Vulnerability Details
CVEID: CVE-2026-7528
DESCRIPTION: Langflow OSS could allow a denial of service due to uncontrolled resource consumption.
CWE: CWE-400: Uncontrolled Resource Consumption
CVSS Source: IBM
CVSS Base score: 7.1
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H)
Affected Products and Versions
| Affected Product(s) | Version(s) |
| Langflow OSS | 1.0.0-1.9.0 |
Remediation/Fixes
IBM strongly recommends addressing the vulnerability now by upgrading Langflow OSS to version 1.9.2.
Workarounds and Mitigations
None
Get Notified about Future Security Bulletins
References
Acknowledgement
This vulnerability was reported to IBM by Ori Lahav (Rubrik Inc.) orilahav@tauex.tau.ac.il.
Change History
19 May 2026: Initial Publication
*The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin.
Disclaimer
According to the Forum of Incident Response and Security Teams (FIRST), the Common Vulnerability Scoring System (CVSS) is an "industry open standard designed to convey vulnerability severity and help to determine urgency and priority of response." IBM PROVIDES THE CVSS SCORES ""AS IS"" WITHOUT WARRANTY OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY. In addition to other efforts to address potential vulnerabilities, IBM periodically updates the record of components contained in our product offerings. As part of that effort, if IBM identifies previously unidentified packages in a product/service inventory, we address relevant vulnerabilities regardless of CVE date. Inclusion of an older CVEID does not demonstrate that the referenced product has been used by IBM since that date, nor that IBM was aware of a vulnerability as of that date. We are making clients aware of relevant vulnerabilities as we become aware of them. "Affected Products and Versions" referenced in IBM Security Bulletins are intended to be only products and versions that are supported by IBM and have not passed their end-of-support or warranty date. Thus, failure to reference unsupported or extended-support products and versions in this Security Bulletin does not constitute a determination by IBM that they are unaffected by the vulnerability. Reference to one or more unsupported versions in this Security Bulletin shall not create an obligation for IBM to provide fixes for any unsupported or extended-support products or versions.
Document Location
Worldwide
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Document Information
Modified date:
19 May 2026
Initial Publish date:
19 May 2026
UID
ibm17273427